Interface engineering of Platinum-Copper alloy/titanium dioxide for enhanced photocatalytic carbon dioxide reduction.

To develop an efficient photocatalytic carbon dioxide (CO2) reduction aimed at mitigating CO2 emissions and greenhouse effects, we propose a straightforward strategy involving hydrogen reduction treatment of PtCu/Ti to create the PtCu/Ti-H2 catalyst with a distinctive interface structure. Compared with the fresh PtCu/Ti catalyst and the benchmark anatase TiO2, the CH4 production of the PtCu/Ti-H2 catalyst increased by 2 times and 81.6 times, respectively. Comprehensive characterizations confirmed the formation of Ptδ+-Ov-Ti3+ and Cuδ+-Ov-Ti3+ interface structures on the hydrogen-treated PtCu/Ti-H2 catalyst, enhancing light absorption and the separation of photogenerated charge carriers. Further investigation into the reaction mechanism revealed that the Ptδ+-Ov-Ti3+ and Cuδ+-Ov-Ti3+ species on PtCu/Ti-H2 serve as more favorable sites for CO2 adsorption and activation, promoting an enhanced formaldehyde mechanism. This study not only elucidates the relation between photocatalytic CO2 reduction activity and the PtCu/Ti interface structure but also offers a novel strategy for designing alloy/oxide-based catalysts for CO2 photoreduction, overcoming the limitations of previous studies that focused on metal or vacancy systems.